Portable kilns

ABSTRACT

A relatively light weight portable kiln which may be quickly and easily disassembled, transported and reassembled. The kiln shown comprises: a cylindrical body, an optional body extender, a disk shaped base which engages the body, a similarly shaped lid, a metallic support frame and a controlled source of heat. The cylindrical body, the base and the lid are vacuum formed members composed of alumina-silica, zirconium or other similar fibrous material which is light weight, strong and capable of acting as an insulator and container of heat at temperatures in excess of 2,000* F. The body, the lid and the base are each covered with a stainless steel exterior surface to protect these elements from mechanical damage. The source of controlled heat shown comprises electric elements supported in retaining recesses in the wall of the cylindrical body.

United States Patent 1191 Colson 1 PORTABLE KILNS [76] Inventor: Frank s. C0150", 1666 Hillview,

Sarosota, Fla. 33579 221 Filed: se nzv, 1971 [21] Appl. No.: 184,122

[56] References Cited UNITED STATES PATENTS 2,466,409 4/1949 Gardes 219/400 X 2,466,349 5/1949 Anderson 219/400 X 3,258,323 6/1966 Kirk 219/385 X 3,500,444 3/1970 Hesse 219/464 X 3,541,293 11/1970 MacDonald et a1. 219/390 3,350,493 10/1967 Randall 13/22 3,086,101 4/1963 Scofield 219/464 X 3,227,798 1/1966 Delange et a1 13/22 3,170,060 2/1965 Oliver, Jr. et al.... 219/390 2,463,329 3/1949 Stansbury 219/422 2,673,228 3/1954 Kistler 13/22 X 14 1 Jan. 15,1974

2,963,529 12/1960 Schmidt 13/22 3,267,529 8/1966 Gruberet a1. 13/31 X 3,491,192 1/1970 Bishop et 1. 13/20 3,646,321 2/1972 siegeaunt 219/464 mary Exam ne .ivqlszslxmysyMaxwhy .7. Attorney-lohn G. Albrecht [57] ABSTRACT A relatively light weight portable kiln which may be .quickly and easily disassembled, transported and reassembled. The kiln shown comprises: a cylindrical body, an optional body extender, a disk shaped base which engages the body, a similarly shaped lid, a metallic support frame and a controlled source of heat. The cylindrical body, the base and the lid are vacuum formed members composed of alumina-silica, zirconium or other similar fibrous material which is light weight, strong and capable of acting as an insulator and container of heat at temperatures in excess of 2,000F. The body, the lid and the base are each covered with a stainless steel exterior surface to protect these elements from mechanical damage. The source of controlled heat shown comprises electric elements supported in retaining recesses in the wall of the cylindrical body.

7 Claims, 3 Drawing Figures PATENTEDJAN 15 I974 m Milli PORTABLE KILNS FIELD OF THE INVENTION This invention relates to the construction of kilns for the heating and maturing of products and particularly to the construction of portable kilns for such purposes.

BACKGROUND OF THE INVENTION Products which require heating are made by many amateur hobbyists, by skilled professional artisans who make unique artistic products in relatively small quan, tities and by those who make commercial quantities in substantially permanentfacilities. The heating of products to achieve maturing and surface finishing is a serious problem for the hobbyist and those professionals who work in relatively small quantities. Traditionally, kilns have been constructed of heavy and bulky refractory materials such as refractory brick. Because of their bulk and weight and the difficulty of constructing a structure which can be easily disassembled into pieces of manageable size it is difficult if not impossible to construct a really portable kiln of such bricks. Furthermore, the initial cost of such traditional kilns is high and in use they present serious maintenance problems. In summary, kilns made in the traditional manner using refractory bricks are expensive, heavy, bulky and difficult to move without incurring mechanical damage.

SUMMARY OF THE INVENTION In accordance with my invention a portable kiln comprises: a body member, a base member, a lid member, a supporting base and a controlled source of heat. The base member, the lid member and the body member are each composed of fibrous ceramic material which is cast to the respective shapes of these members which are shaped and proportioned to form a heat containing kiln when placed in abutting, engaging relation.

Advantageously, a kiln so constructed is efficient, relatively light in weight, mechanically strong, easily disassembled into pieces which can be easily moved without strain and fear of mechanical damage and can be readily reassembled and ready for use in a relatively short period of time.

This invention will be readily understood by reference to the following description when read with respect to the drawing in which:

FIG. 1 is general overall diagram of an assembled kiln;

FIG. 2 shows in cross section members; and

FIG. 3 is a cross section showing an optional body extender. I

FIG. 1 is an exterior view of an assembled portable the details of the kiln kiln. The body member 100, the base member 101 and' the lid member 102 are all composed of cast fibrous ceramic materials. Materials which satisfy the requirements of construction of a kiln in accordance with my invention are light in weight, capable of withstanding constant heat in the range of 2300 F and admit of casting into mechanically strong shapes. By way of example, alumina-silica ceramic fibers and zirconium fibrous materials have characteristics which allow their use in lustrative embodiment shown inFIGS. l, 2 and 3 electhe construction of my portable kiln. Compared to refractory bricks, an equal volume of alumina-silica fibrous material has approximately one fortieth the weight of the bricks. Alumina-silica fibrous materials have a normal constant heat use of 2300 F, but can be used at even higher temperatures since the melting point of such material is approximately 3600 F. This material is commercially prepared in electric furnace by melting white alumina ore with flint and borax glass to approximately 3600 F. The resulting melt is subjected to a jet stream blast while being poured. This results in a fluffy, white, bulk ceramic fiber up to about 10 microns in diameter and approximately 1 /2 inches long. These fibers can be used in a variety of ways including but not limited to vacuum cast shapes such as the body, base and lid members of my portable kiln. Members so formed can withstand severe thermal shock, constant hightemperature and direct flame, hot acids and even molten aluminum. The alumina-silica fibers interlock during vacuum casting to form strong structural forms and the fibers retain their individual strength and resiliance. A vacuum cast member of alumina-silica fibrous material two inches .thick is thermally equivalent to a brick wall approximately 15 inches thick.

As seen in FIG. 1 the body member, the base member and the lid member are each cast in one piece without joints. This omission of joints advantageously eliminates the loss of heat which occurs in refractory brick kilns because of contraction and expansion. The surface characteristics of vacuumcast kiln members of alumina-silica fibrous materials may be improved 'to give protection against weathering and flame abrasion by the application of commercially available liquid coating cement. Such surface treatment of the interior surfaces is desirable but not essential. One commercially available cement is sold under the name Fiberfrax QF-l80. The exterior surfaces of the body, base and lid members are each mechanically protected byindividual metallic shields which are shown in FIG. 2. These shields may advantageously be made of stainless steel.

The kiln comprising the body, base and lid members is supported on a firm and level open stand 103. This stand supports the base member 101 off the supporting surface and permits the flow of air around the kiln to remove excess heat. The dimensions and shape of the stand 103 are not critical so long as the stated intended purposes are served. I

The peep holes 105 are of size, shape and number to permit visual inspection of the products being heated. These holes are closed by'me'ans of refractory plugs made of the same material as the body members.

The box labeled 104 in FIG. 1 represents controls for maintaining the desired heat within the kiln. In the iltric heating coils are employed. Gas or other fuels may also be used as a source of heat with only slight variation in detailed construction of my kiln as described later herein.

The members 100, 101 and 102 are shown in cross section in FIG. 2. The correspondence of elements in FIGS. 1 and 2 may be understood from the labels used in these FIGS. The body member 200 in FIG. 2 corresponds to the body member in FIG. 1, the lid member 202 corresponds to the lid member 102, etc.

In the illustrative embodiment the body member 100 is cylindrical. The ends of the cylinder are recessed at the outer surface to receive mating flanges of the base and lid members respectively. In the illustrative embodiment the base and lid members are identical in size and shape and may be functionally interchanged.

The electric heating elements are supported in recesses 206 in the wall of the body member 200. These recesses comprise an opening in the interior surface of the body of sufficient size to permit the placement of the heating elements and a depression, as shown in FIG. 2, to receive the heating element and retain it in place in the recess. The heating elements 207 are connected to the control 104 which in turn is connected to a source of electric power which is not shown. The recesses 206 and the heating elements are proportioned so that no part of the heating element is exposed directly to the interior of the kiln.

The function and fabrication of the metal protecting shields 220 are clear from the prior discussion thereof.

The base section, shown in cross section in FIG. 2, is a flat disk with an edge flange 208 depending therefrom. The flange 208 is proportioned to engage the exterior recess in the lower end of the body member 200. When in abutting relation, the body member 200 and the base member 201 form a heat seal. The lid member 202, for ease of manufacture, corresponds in size and shape to the base member 201 and is proportioned to engage the upper recess in the body member 200 to complete the kiln heating compartment.

If it is desired to have a kiln of greater height than that provided by the body member 100, the body extender 301 of FIG. 3 may be utilized between the body member 100 and the lid member 102. The body extender is cylindrical in shape and has a flange 311 at one end to engage the upper recess in the body 100 and a recess 310 at the other end to engage the flange 211 of the lid member. The body extender may alternatively be inverted and placed between and in abutting relation with the base member 101 and the body member 100.

In the event that it is desired'to have a kiln fired with fuel such as gas, the electric elements may be deleted and a commercially available gas burner is introduced through a hole (not shown) in the base member 101. In this event a hole (not shown) is placed in the lid member 102 to act as a flue. The hole in the base member may be in the order of 2 to 3 inches in diameter and the hole in the lid member 4 to 6 inches in diameter. In this case the recesses 206 in the interior surface of the body member 200 are advantageously omitted and the interior surface is smooth.

Portable kilns may be constructed in accordance with my invention-with variations from the illustrative embodiment shown in the drawing and described herein. For example, the method of engaging the case and lid members with the body may be changed. Similarly the body may be other than cylindrical in shape.

The heat control 104 and the heat elements 207 are arranged to allow a typical heating procedure as follows:

a. Slow gradual heat buildup not to exceed 900 F.

within 1 to 3 hours;

b. Accelerated heat buildup to approximately 1,500

to 1,850F within an additional period of three hours; and

c. Maximum heat peak of approximately 2,400 F, but not less than 2,300 F within an additional 3 hours.

What is claimed is:

1. A portable kiln comprising: a unitary substantially rigid homogeneous self-supporting tubular body member comprising first and second end surfaces, a unitary homogeneous substantially rigid base member for mechanically engaging said first end surface and complementary thereto to provide physical stability between said body and base member and to provide a heat seal a unitary homegeneous substantially rigid lid member for mechanically engaging said second end surface and shaped complementary thereto to provide physical stability between said body and said lid and to provide a heat seal, a supporting base for receiving said base member, and a controlled electric source of heat in said kiln said body, base and lid members being shaped and proportioned to form a heat containing chamber for receiving goods to be heat treated when said members are placed in abutting and engaging relation; and said body, base and lid members each being of substantially non-porous fibrous ceramic material having a relatively low thermal transmission characteristic cast to the respective shapes of said members.

2. A portable kiln in accordance with claim 1 wherein said fibrous ceramic material comprises alumina-silica ceramic fibers.

3. A portable kiln in accordance with claim 1 wherein said fibrous ceramic material comprises zirconium ceramic fibers.

4. A portable kiln in accordance with claim 1 wherein said body member comprises an open ended cylinder, the ends of said cylinder being recessed at the outer cylindrical surface to form a ring at each end of said body member; and said base member and said lid member are fiat circular members and are recessed to receive respective ones of said rings.

5. A portable kiln in accordance with claim 1 wherein said body member is equipped with peep holes for viewing material being processed in said kiln.

6. A portable kiln in accordance with claim 4 wherein said cylindrical body has a plurality of recesses in the inner surface of thebody, said recesses being spaced apart along the length of said body and concen tric therewith, said recesses being adapted to receive and securely hold a plurality of heating elements corresponding in number to said plurality of recesses.

7. A portable kiln comprising a cylindrical shaped open ended body member, the ends of said cylinder being recessed to form at least one ring at each end of said cylinder; a circular flat base member and a circular fiat lid member, said base member and said lid member each provided with circular recesses to provide surfaces which mate with respective ones of said rings to provide a heat seal; said body member being provided with a plurality of circular shaped recesses spaced apart along the length of said body and concentric therewith a plurality of heating element 5,, said recesses being shaped to receive and hold said plurality of heating elements corresponding in number to said plurality of recesses, means for coupling said heating elements with a source of electric power and means for measuring the temperature within said kiln and for controlling said application of power in response thereto. 

2. A portable kiln in accordance with claim 1 wherein said fibrous ceramic material comprises alumina-silica ceramic fibers.
 3. A portable kiln in accordance with claim 1 wherein said fibrous ceramic material comprises zirconium ceramic fibers.
 4. A portable kiln in accordance with claim 1 wherein said body member comprises an open ended cylinder, the ends of said cylinder being recessed at the outer cylindrical surface to form a ring at each end of said body member; and said base member and said lid member are flat circular members and are recessed to receive respective ones of said rings.
 5. A portable kiln in accordance with claim 1 wherein said body member is equipped with peep holes for viewing material being processed in said kiln.
 6. A portable kiln in accordance with claim 4 wherein said cylindrical body has a plurality of recesses in the inner surface of the body, said recesses being spaced apart along the length of said body and concentric therewith, said recesses being adapted to receive and securely hold a plurality of heating elements corresponding in number to said plurality of recesses.
 7. A portable kiln comprising a cylindrical shaped open ended body member, the ends of said cylinder being recessed to form at least one ring at each end of said cylinder; a circular flat base member and a circular flat lid member, said base member and said lid member each provided with circular recesses to provide surfaces which mate with respective ones of said rings to provide a heat seal; said body member being provided with a plurality of circular shaped recesses spaced apart along the length of said body and concentric therewith a plurality of heating elements, said recesses being shaped to receive and hold said plurality of heating elements corresponding in number to said plurality of recesses, means for coupling said heating elements with a source of electric power and means for measuring the temperature within said kiln and for controlling said application of power in response thereto. 